The present invention, in some embodiments thereof, relates to optoelectronics and imaging, and more particularly, but not exclusively, to light patterning and computer vision imaging.
The use of cameras in computer systems, commonly termed computer vision, continues to increase. Video conferencing, live feeds and the like are common applications that require computer vision, and advanced user interfaces that use computer vision are becoming increasingly available for desktop, home, and mobile computing devices.
Conventional camera applications involve the use of a camera operator who controls the camera, and, in particular, controls the image that the camera records by appropriately orienting the camera. The camera operator may also provide direction to improve the appearance of the objects being recorded. In the terminology common to the field, proper image framing assures that a desired image is included within the field of view of the camera. A typical computer vision application is often operated using a fixed position camera and no camera operator per se.
Some computer vision systems employ stereo camera systems to acquire three-dimensional information about objects. Typical stereo camera systems include two or more electronic cameras which are mounted at spaced apart locations. The electronic cameras have partially overlapping fields of view. A computer connected to receive images from each of the cameras can compare the images to derive three-dimensional information about objects in the field of view. Information such as the distances to the objects and the sizes, dimensions and orientations of the objects can be determined by triangulation.
Currently available stereo camera systems use small cameras which have arrays of light sensing elements such as charge coupled devices (CCDs), matrix complementary metal oxide semiconductor (CMOS) sensors or the like. A typical camera, as is used in a typical stereo camera system, comprises a circuit board on which a light sensing array is mounted. A lens is supported above the light sensing array by a lens holder. The entire camera is mounted by the circuit board to a suitable support in a desired position relative to other cameras in the stereo camera system.
In the art of digital imaging, particularly for the purpose of computer vision, the current trend is to eliminate the effect of infrared ((IR) light upon the image sensors. This traditional need arises because the most common semiconductor-based image sensing devices respond not only to visible light, but also to IR light in the wavelength range of approximately 680 to 1100 nanometers. Responses to IR light are known to distort the image so that traditional digital imaging techniques are unable to obtain a high-quality color image, or correctly preserve scene luminance in monochrome imagers. The effect of IR light is typically eliminated using CCD or CMOS based image sensors which are supplemented by an IR CUT filter. The IR CUT filter is part of the optical path, either positioned over the imager sensor array or overlying the lens or interposed within other optical elements.
In the field of image capturing and analysis, light pattern illumination is oftentimes employed. In light pattern illumination, a scene is being illuminated by a light source possibly via a mask of some kind so that a specified geometric pattern of illumination is achieved. After capturing the scene with capturing device such as a camera, the captured images (or video) can be analyzed taking into account the predefined illumination pattern. The prior knowledge about the illumination pattern geometry facilitates the image processing and assist in determining, among other things, a depth map of the scene.